Semiconductor Structure Fabrication Without Sacrificial Layers
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Solution Overview
Problem
Traditional methods for fabricating through-silicon-vias (TSVs) and trench-type capacitors simultaneously are complex and costly, primarily due to the use of sacrificial layers in the fabrication process.
Innovation Solution
A semiconductor structure and fabrication method that form both TSVs and trench-type capacitors using a process that skips the use of sacrificial layers, employing laser drilling, dry etching, and chemical vapor deposition to create recesses and conductive layers, allowing for a simpler and less expensive process flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fabricating methods with sacrificial layers are used, then TSVs and trench-type capacitors can be formed simultaneously, but the fabrication process becomes complex and costly
Solution Approach 1:
The patent removes the sacrificial layer step from the fabrication process entirely. Instead of forming trenches with sacrificial layers and then removing them, the method directly forms recesses to the required depths and fills them with conductive materials. This extraction of the sacrificial layer process eliminates the associated complexity and cost while maintaining the ability to form both TSVs and capacitor structures simultaneously.
Solution Approach 2:
The patent segments the fabrication process by forming the first recess to a greater depth than the second recess, allowing selective exposure of conductive layers after substrate thinning. This segmentation enables different structures (TSV vs. capacitor) to be formed in the same substrate using the same basic process steps, reducing overall process complexity.
2Reliability
If sacrificial layers are used in fabrication steps, then TSVs and trench-type capacitors can be formed, but the manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the sacrificial layer process from the manufacturing flow. By directly forming recesses and filling them with conductive materials, the patent removes the additional material deposition and removal steps required for sacrificial layers, thereby reducing manufacturing cost while maintaining the dual functionality of TSV and capacitor formation.
3Reliability
If the substrate is thinned to expose conductive layers, then via structures can be formed, but the first conducting layer in the second recess may be exposed
Solution Approach 1:
The patent performs preliminary action by forming the first recess to a greater depth than the second recess before substrate thinning. This pre-positioning of the first recess deeper into the substrate ensures that when the substrate is thinned from the backside, the conductive layer in the second recess remains protected and is not exposed, eliminating the need for precise real-time control during the thinning process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method reduces the complexity and cost of the fabrication process while maintaining the capacitance density advantage of trench-type capacitors, enabling efficient integration in semiconductor devices.
Implementation Method 1
forming the first recess and the second recess are by laser drilling
Implementation Method 2
forming the first conducting layer and the second conducting layer are by chemical vapor deposition (CVD)
Data Source
AI summary
A semiconductor structure and a method of fabricating thereof are provided. The method includes the following steps. A substrate with an upper surface and a lower surface is received. A first recess extending from the upper surface to the lower surface is formed and the first recess has a first depth. A second recess extending from the upper surface to the lower surface is formed and the second recess has a second depth less than the first depth. A first conducting layer is formed in the first recess and the second recess. A first insulating layer is formed over the first conducting layer. A second conducting layer is formed over the first insulating layer and isolated from the first conducting layer with the first insulating layer. The substrate is thinned from the lower surface to expose the second conducting layer in the first recess.